Large cabinet specimen featuring numerous brown to olive-brown bladed and lenticular Siderite crystals associated with bright brassy-golden Chalcopyrite. The contrasting metallic Chalcopyrite is distributed throughout the crystallized surface, creating a rich three-dimensional composition characteristic of specimens from the Kaiwu Mine. The specimen comes from an old Danish private mineral collection and retains its original historical label identifying it as Siderite with Chalcopyrite from the Kaiwu Mine, China.